Is there a way to determine if the boiler or the radiators are to blame for pressure drop
Anonymous user 14/03/2024 - 2.37 PM
We had a brand new boiler installed probably 2-3 months ago. Within a week of installation, pressure slowly started to drop and needing to be topped up every few days. When I contacted the installation company, they convinced that the new boiler will do that and will be ok after topping up pressure a few times. But gradually, it got worse and now I need to top up at least 1-2 times a day. I've checked all the radiators and cannot see obvious signs and our old boiler never ever dropped pressure once. I spoke to someone at the desk (not installer) and he suggested to isolate central heating and whilst doing that the central heating pressure dropped but not the boiler (I have viessman, which also has manual guage which I assume for central heating, which lost pressure) but the digital guage from the boiler stayed put. Thus, he concluded it is the central heating fault. He says I need to find someone else to look at the central heating.
Is his testing valid? I have hard time believing it is the central heating as I never had to top up once with the old boiler. What option do I have?
Thank you in advance.
Are you a tradesperson and able to answer this question?
There are a few potential causes of heating pressure loss on your system:
- A leak in your heating pipework (you would likely have noticeable wet patches in your property if this was the case)
- Expansion vessel needs to recharged or replaced (this is unlikely on a new boiler, but possible)
- Pressure relief valve is faulty, and discharging water
- Radiators need bleeding (feel the the top of the radiators, if they're cold then they need a bleed). If they do, bleed them in turn starting from the closest radiator to ground level, furthest from the boiler, and work your way higher and closer the boiler.
Without being able to look at the system hands-on, I can't say for sure what the exact cause of the fault is. Worth bleeding the radiators as your first port of call as it's simple and free to do. If that doesn't do it (and you haven't noticed a massive leak) then the fault is almost certainly on the boiler. In this case it would be worth getting a registered heating engineer to have a look and properly diagnose the fault.
Hope this helps!
From my experience if the pressure drops for any reason after doing work to your pipes regardless of a new boiler or not there most likely will be a small leak somewhere. In most cases people have changed radiators or taken them off to decorate behind them and the valve leaks a tiny bit that you barely see which will cause the pressure to drop. Or the pressure vessel has gone and needs to be replaced, a good way to indicate you need a new one is if your pressure gauge is on lets say 1 bar, fit the nozzle of an ordinary everyday pump (like a bike pump) to your vessel and if it instantly squirts out water you’ll need a new one, it means its not working as it should. Or if you’ve changed taps or showers or anything that includes your pipe work there is more likely a leak somewhere.
The best way to discover whether the leak is on the boiler or central heating is to fill the pressure between 1 - 1.5 bar pressure ( boiler cold ), isolate the 2 heating service valves under the boiler, leave to test for a few hours and see if the pressure as dropped or not. This really should be done by a GasSafe engineer , I do like the options given by the first engineer but I am not in favour of the leak sealant to be added to the system but it is also another option.
Answered22 February 2024
1
Anonymous user
Isolate boiler at flow and return valves and leave for 24 hours. If pressure continues to drop it’s the boiler, if it doesn’t it’s the pipework/ radiators
